#include <iostream>
#include <numeric>
using namespace std;
int main() {
  double inverseFact[16];
  inverseFact[0] = 1;
  for (int i = 1; i < 16; i++) {
    inverseFact[i] = inverseFact[i - 1] / i;
  }
  int n;
  cin >> n;
  // double e = 0;
  // for (int i = 0; i <= n; i ++) {
  //   e += inverseFact[i];
  // }
  cout << fixed;
  cout.precision(10);
  cout << accumulate(inverseFact, inverseFact + n + 1, 0.0) << endl;
}